This invention generally relates to mobile telecommunications and more particularly to a method and system for terminating invalid mobile telephones.
Fraudulent use of the network of a mobile service provider, or vendor, is a major concern with losses for 1995 estimated at $650 million. Vendors in the major metropolitan areas are especially susceptible to losses caused by "clones" which are reported to account for 90% of the total revenue losses due to fraud. The best protection against cloning is authentication, but unfortunately, there are close to forty million phones in the market that are not authentication capable. In addition to authentication, a number of fraud prevention methods have been developed to deal with the cloning problem. These other techniques include techniques known as PIN encoding, roamer verification reinstatement, call profiling and radio frequency, or RF, fingerprinting.
Some of those techniques cannot directly interface with the MSC to terminate a "suspected" call. For example, even if an RF fingerprint detection system detects a clone, the call is still established. There is no capability to block a call origination.
The present inventors have determined that in order to effectively use external fraud management applications, a reliable method of tearing down a suspected call is required. This need is believed to be especially critical for applications using the RF fingerprinting technique in which generally the RF fingerprinting equipment is installed at a cell site and passively monitors call attempts. The unique RF pattern, or fingerprint, associated with each analog mobile telephone is stored for future reference. On any new call origination, the RF fingerprint is compared with the one stored, and if there is no match, the RF application detects a fraudulent call.
The present inventors have also determined that there is also a need for reliable method and apparatus for tearing down a so-called "pre-paid call" by a subscriber that is allowed to make a limited amount of calls on a pre-paid basis. Once the pre-paid credit is exhausted during the course of a metered call, there is a need to tear down the currently active call in association with generation of an automatic message accounting, or AMA, record.
It has also been determined by the inventors that there is also a need to enable tear-down of an active call by manual intervention by an operator via a Technician Interface (TI) command.